This invention relates in general to the bundling of products for shipping convenience and more particularly to an apparatus and method of bundling loose or bulk products, for example magazines, using a wrapping process that includes binding material that is removable without damaging the bulk products.
Plastic strapping and shrink wrapping are currently the industry standard for securing loose stacks of paper products. Plastic strapping includes one or more straps around a bundle that are not usually fixed to the bundle.
In a traditional plastic strapping process, pre-stacked products such as magazines form a loose stack or bundle that are conveyed out of a stacking mechanism and through a strapping machine. With the aid of a photo eye or some sensory trigger, the strapping cycle is initiated when a strap is fed or pushed through an existing track that forms a hoop that encircles the bundle at a diameter larger than the bundle. The end of the strap makes contact with a clamping mechanism and the feed process is reversed to take up the slack in the strap, thereby liberating the strap from the track and bringing the strap into contact around the bundle. When the tension on the strap reaches a predetermined value, the strap is heat-sealed to the clamped end and then the strap is cut. It is noted that in this traditional plastic strapping process, there is no direct attachment of the strap to the bundle other than the friction caused by the bundle pushing against the hoop strength of the pre-tensioned strap. Additionally, there is currently no widely used or accepted automatic system for removal of the plastic straps from the bundles. Therefore, the plastic straps must be manually removed and this removal includes cutting and discarding the strap or sliding the strap off the end of the bundle.
While a majority of all bundles today reach their destination after being secured in some fashion by wrapping and or strapping as described above, this type of plastic wrapping has a number of disadvantages. To make a durable bundle that will not become loose during shipment, the strap is often installed around the bundle too tightly, thus causing the bundled products to deform and, in some cases, become damaged such that the bundle cannot be reintroduced into any further automated processes. In fact, the damage can be so great that the bundle must be discarded as a damaged product. When the plastic strap is installed loosely enough to prevent the bundle paper products from being deformed and damaged, the plastic strap is often too loose to allow the bundle to be reliably palletized automatically. Additionally, the loose plastic wrapping also makes for unstable manually palletized loads that must themselves be wrapped and strapped. Strapping equipment also has a higher incidence of downtime and a shorter mechanical life span that other equipment in printing industry environments. This is a function of the speed per minute that the bundles must be wrapped. To further exacerbate these problems, the plastic straps must be removed manually from the bundles for further automated processing.
In an alternate form of strapping, the material to be shipped is wrapped with a material that shrinks when warmed, thereby securing the wrapping to the material and generating a secured shipping bundle. In this “shrink wrapping” process, pre-stacked products such as magazines, are positioned to form a loose stack or bundle that are then conveyed out of the stacking mechanism. The stacks are widely spaced via some conveyance medium, usually over two successively faster belt conveyors. The stacks are conveyed without stopping through a machine that has two rolls of film—one over and one under the product. The two rolls of film are joined and cut by a heated wand that melts the two lengths of film together. As the stack moves past the joined rolls, it takes the film with it, both over and under the bundle. When the stack has passed the heated cut-off wand, the two layers of film are cut and joined in one process. The film enshrouded stack is then conveyed through a heat tunnel where hot air causes the film to shrink, thus creating tension and holding the bundle together. The bundle is conveyed out of the heat tunnel and cooled in ambient air.
Once the bundle wrapped by the shrink wrapping process has reached its shipping destination, the shrink wrap material must be removed. There is currently no widely used or accepted automatic system for removal of heat shrink film from bundles. Manual removal of the shrink wrap from the bundle includes cutting and discarding the wrap.
Shrink wrapping has some advantages. For example, the film's coefficient of friction against itself is quite good for use in making pallet loads that are more stable. The bundle also becomes stronger than a stack by itself, thus helping to prevent product damage and paper folding. And, as in the previously described strapping process, most of all bundles usually reach their destination when secured in some shrink wrapped fashion.
However, there are also a number of disadvantages associated with shrink wrapping. For example, shrink wrapping equipment includes a high temperature tunnel that is easily misadjusted thereby causing improper wrapping. During the shrink wrapping process, a bundle stopped in the heat tunnel used to heat and shrink the wrapping material can also ruin the bundle due to the heat, or can actually cause the bundle to burst into flames. The shrink wrapping process also requires burning products that give off potentially toxic gasses and can potentially burn the products.
The completion of the shrink wrapping process also requires extensive use of factory floor space because the bundles must be conveyed down a longer out-feed conveyor needed to allow the heated shrink wrap to cool down. If there is a conveying problem that causes the shrink wrapped bundles to touch each other before the shrink wrap has cooled, the hot bundles can stick to each other. Finally, the shrink wrap material must also be removed manually from bundles for further automated processing making the removal of the shrink wrap labor intensive.
The above bundle packaging methods also present other problems. Bundles of bulk paper items must be transportable without falling apart. The above bundle packaging methods may result in bundles that are too loose or too weak, resulting in unstable loads and loosely strapped bundles that fall apart. While the preferred bundle packaging process must not change its contents, the above examples may result in products damages by crimped bindings, burns, tears, rolled or bent edges, and football-shaped bundles. The above bundle packaging processes are also excessively labor intensive during the process of removing the wrapping material.
A preferable bundle packaging method would likely have a number of preferable characteristics. For example, bundles should maintain bundle integrity for automatic handling of the bundle, such as palletizing, depalletizing, conveying, and sorting, etc. The bundle packaging material should also be automatically removable and include automatic waste removal. Machinery for applying and removing packaging should be reliable with respect to speed, maintenance, and life expectancy. Finally, the packaging material costs for any new packaging process must not exceed current packaging costs. The above-described packaging methods do not offer all of these advantages.
While the embodiment of the present invention is illustrated in the above-referenced drawings and in the following description, it is understood that the embodiment shown is merely for purpose of illustration and that various changes in construction may be resorted to in the course of manufacture in order that the present invention may be utilized to the best advantage according to circumstances which may arise, without in any way departing from the spirit and intention of the present invention, which is to be limited only in accordance with the claims contained herein.